All of lore.kernel.org
 help / color / mirror / Atom feed
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Jakub Kicinski <kuba@kernel.org>, davem@davemloft.net
Cc: netdev@vger.kernel.org, willemb@google.com,
	eric.dumazet@gmail.com, dsahern@gmail.com,
	yoshfuji@linux-ipv6.org, Dave Jones <dsj@fb.com>
Subject: Re: [PATCH net-next v3] net: ip: avoid OOM kills with large UDP sends over loopback
Date: Wed, 23 Jun 2021 20:05:05 +0200	[thread overview]
Message-ID: <d4de9fa3-3170-af6e-719a-4c809dca81b4@gmail.com> (raw)
In-Reply-To: <20210623162328.2197645-1-kuba@kernel.org>



On 6/23/21 6:23 PM, Jakub Kicinski wrote:
> Dave observed number of machines hitting OOM on the UDP send
> path. The workload seems to be sending large UDP packets over
> loopback. Since loopback has MTU of 64k kernel will try to
> allocate an skb with up to 64k of head space. This has a good
> chance of failing under memory pressure. What's worse if
> the message length is <32k the allocation may trigger an
> OOM killer.
> 
> This is entirely avoidable, we can use an skb with page frags.
> 
> af_unix solves a similar problem by limiting the head
> length to SKB_MAX_ALLOC. This seems like a good and simple
> approach. It means that UDP messages > 16kB will now
> use fragments if underlying device supports SG, if extra
> allocator pressure causes regressions in real workloads
> we can switch to trying the large allocation first and
> falling back.
> 
> Reported-by: Dave Jones <dsj@fb.com>
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---

Reviewed-by: Eric Dumazet <edumazet@google.com>

Thanks !


  reply	other threads:[~2021-06-23 18:05 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-23 16:23 [PATCH net-next v3] net: ip: avoid OOM kills with large UDP sends over loopback Jakub Kicinski
2021-06-23 18:05 ` Eric Dumazet [this message]
2021-06-23 18:11   ` Eric Dumazet
2021-06-23 19:45 ` Jesper Dangaard Brouer
2021-06-23 21:07   ` Jakub Kicinski
2021-06-24  2:23     ` Willem de Bruijn
2021-06-23 21:14   ` Eric Dumazet

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=d4de9fa3-3170-af6e-719a-4c809dca81b4@gmail.com \
    --to=eric.dumazet@gmail.com \
    --cc=davem@davemloft.net \
    --cc=dsahern@gmail.com \
    --cc=dsj@fb.com \
    --cc=kuba@kernel.org \
    --cc=netdev@vger.kernel.org \
    --cc=willemb@google.com \
    --cc=yoshfuji@linux-ipv6.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.